Can Your Genes Explain Sexual Orientation?

Genetic testing can explain many things. Is your sexual orientation one of them?

BY Diane Anderson-Minshall

October 30 2012 1:00 PM ET

In the 1997 film Gattaca, Ethan Hawke’s character attempts to circumvent the genetic screening that is the basis of contemporary life. When Vincent Freeman (Hawke) is a newborn baby, a routine heel-tap blood test reveals his entire medical future — a rather far-fetched scenario, but one that speaks to concerns about the role of authenticity, science, and technology in today’s fast-paced global environment.

The future is upon us, and the genetic testing being done now can reveal the past as much as it illuminates the future. The first wave of LGBT consumers who embraced it did so to find out about their ancestry. But as testing organizations, particularly 23andMe, the largest and most popular DNA analysis service, grow their databases, consumers are learning many more things about their lives, including which medications they’re likely to have reactions to, whether they have the gene thought to confer immunity to HIV, or — soon — if there’s a genetic root to their sexual orientation.

How it works is simple: Customers buy a saliva kit online at 23andMe.com, send it in, and the company extracts their DNA from cheek cells preserved in saliva. In its labs, 23andMe then copies the DNA many times until there’s enough to be genotyped. Then, says lesbian scientist Emily Drabant, the DNA is examined for tens of thousands of genetic variants linked to various conditions and traits, and within weeks users get more than 100 reports on diseases, more than 50 reports on traits, more than 40 reports on carrier status, and more than 20 for drug response.

Drabant, who has a Ph.D. in neuroscience, joined 23andMe three years ago. “I came on board to manage our Parkinson’s research, which at the time was one of our largest research projects,” she says. Though she works on all brain disease research, including healthy cognitive aging, boxing and head trauma, and Alzheimer’s, she’s proud of the Parkinson’s research in particular, because of the results. “We now have one of the largest cohorts of Parkinson’s patients, genotyped patients, in the world — over 9,000 people with Parkinson’s. And we identified two new genes associated with Parkinson’s, which is really exciting.” By having such a large study group, Drabant says, 23andMe was able to explore the genes versus environment question as it relates to the disease. “Within that, we found that, in the part that’s genetic, we know less than 10% of the genes involved. So I think it’s very exciting that there’s still a lot left to discover.”

Indeed, as LGBT consumers have used 23andMe to obtain their genetic background, they’ve found plenty of information that is specific to their needs, like cancer risks, HIV resistance and likely progression rate, medication complications, whether they’re prone to substance abuse, who their genetic ancestors are, and whether they are carriers for diseases that put children at risk. For soon-to-be biological parents, screening for these factors can cost $1,000 per test at a typical medical lab; with 23andMe, a couple hundred bucks tells you the results of dozens of tests, such as that for Tay-Sachs. The company can even tell you if that double venti latte is likely to give you a heart attack.

“We’ve taken great care to make genetics understandable to a lay audience, because it’s really complicated,” Drabant says. “So one of the ways we try and do it is by using pictures. We often call these the Waldos.” The Waldos are really a pictogram of 100 people with Waldos, so called because of the similarity to the Where’s Waldo? character. A first set of Waldos demonstrates the frequency of the disease or condition in the population, while a second set shows the frequency of the disease in the population with a specific genetic factor. This helps illusrate the impact a genetic factor has on overall risk of a disease. “So if you have increased risk, you have many more Waldos colored in.”